add a sample of FLUX code

These samples were taken from the paper "Flux: A Language for
Programming High-Performance Servers", by Burns et al and Flux V0.02
which can be found here:

https://plasma.cs.umass.edu/emery/flux.1.html

samples/FLUX/imageserver.fx

@@ -0,0 +1,44 @@
+typedef xml TestXML;
+typedef html TestHTML;
+
+typedef inCache TestInCache;
+
+Page (int socket) => ();
+
+ReadRequest (int socket) => (int socket, bool close, image_tag *request);
+
+CheckCache (int socket, bool close, image_tag *request) 
+	=> (int socket, bool close, image_tag *request);
+
+Handler (int socket, bool close, image_tag *request)
+     => (int socket, bool close, image_tag *request);
+
+Complete (int socket, bool close, image_tag *request) => ();
+
+ReadInFromDisk (int socket, bool close, image_tag *request)
+     => (int socket, bool close, image_tag *request, __u8 *rgb_data);
+
+Write (int socket, bool close, image_tag *request)
+     => (int socket, bool close, image_tag *request);
+
+Compress(int socket, bool close, image_tag *request, __u8 *rgb_data)
+	=> (int socket, bool close, image_tag *request);
+
+StoreInCache(int socket, bool close, image_tag *request)
+	=> (int socket, bool close, image_tag *request);
+
+Listen () 
+	=> (int socket);
+
+source Listen => Page;
+
+Handler:[_, _, inCache]=;
+Handler:[_, _, _]=ReadInFromDisk -> Compress -> StoreInCache;
+
+Page = ReadRequest -> CheckCache-> Handler -> Write -> Complete;
+
+atomic CheckCache:{cache};
+atomic StoreInCache:{cache};
+atomic Complete:{cache};
+
+handle error ReadInFromDisk => FourOhFor;